与 Secret 的区别：
ConfigMap 保存的是不需要加密的、应用所需的配置信息。 ConfigMap 的用法几乎与 Secret 完全相同：可以使用 kubectl create configmap 从文件或者目录创建 ConfigMap，也可以直接编写 ConfigMap 对象的 YAML 文件。1.1 通过命令行参数--from-literal创建
创建命令：
[root@kub-k8s-master prome]# kubectl create configmap test-configmap --from-literal=user=admin --from-literal=pass=1122334 configmap/test-configmap created结果如下面的data内容所示：
[root@kub-k8s-master prome]# kubectl get configmap test-configmap -o yaml apiVersion: v1 data: pass: "1122334" user: admin kind: ConfigMap metadata: creationTimestamp: "2019-10-21T07:48:15Z" name: test-configmap namespace: default resourceVersion: "187590" selfLink: /api/v1/namespaces/default/configmaps/test-configmap uid: 62a8a0d0-fab9-4159-86f4-a06aa213f4b11.2 通过指定文件创建
编辑配置文件app.properties内容如下：
[root@kub-k8s-master prome]# vim app.properties property.1 = value-1 property.2 = value-2 property.3 = value-3 property.4 = value-4 [mysqld] !include /home/wing/mysql/etc/mysqld.cnf port = 3306 socket = /home/wing/mysql/tmp/mysql.sock pid-file = /wing/mysql/mysql/var/mysql.pid basedir = /home/mysql/mysql datadir = /wing/mysql/mysql/var创建（可以有多个--from-file）：
[root@kub-k8s-master prome]# kubectl create configmap test-config2 --from-file=app.properties configmap/test-config2 created结果如下面data内容所示：
[root@kub-k8s-master prome]# kubectl get configmap test-config2 -o yaml apiVersion: v1 data: app.properties: | property.1 = value-1 property.2 = value-2 property.3 = value-3 property.4 = value-4 [mysqld] !include /home/wing/mysql/etc/mysqld.cnf port = 3306 socket = /home/wing/mysql/tmp/mysql.sock pid-file = /wing/mysql/mysql/var/mysql.pid basedir = /home/mysql/mysql datadir = /wing/mysql/mysql/var kind: ConfigMap metadata: creationTimestamp: "2019-10-21T08:01:43Z" name: test-config2 namespace: default resourceVersion: "188765" selfLink: /api/v1/namespaces/default/configmaps/test-config2 uid: 790fca12-3900-4bf3-a017-5af1070792e5通过指定文件创建时，configmap会创建一个key/value对，key是文件名，value是文件内容。
1.3 指定目录创建
configs 目录下的config-1和config-2内容如下所示：
[root@kub-k8s-master prome]# mkdir config [root@kub-k8s-master prome]# cd config/ [root@kub-k8s-master config]# vim config1 aaa bbb c=d [root@kub-k8s-master config]# vim config2 eee fff h=k创建：
[root@kub-k8s-master config]# cd .. [root@kub-k8s-master prome]# kubectl create configmap test-config3 --from-file=./config configmap/test-config3 created结果下面data内容所示：
[root@kub-k8s-master prome]# kubectl get configmap test-config3 -o yaml apiVersion: v1 data: config1: | aaa bbb c=d config2: | eee fff h=k kind: ConfigMap metadata: creationTimestamp: "2019-10-21T08:20:42Z" name: test-config3 namespace: default resourceVersion: "190420" selfLink: /api/v1/namespaces/default/configmaps/test-config3 uid: 6e00fded-80a8-4297-aeb3-4c48795e6eb9指定目录创建时，configmap内容中的各个文件会创建一个key/value对，key是文件名，value是文件内容。
1.4 通过事先写好configmap的标准yaml文件创建
yaml文件内容如下： 注意其中一个key的value有多行内容时的写法
[root@kub-k8s-master prome]# vim configmap.yaml --- apiVersion: v1 kind: ConfigMap metadata: name: test-config4 namespace: default data: cache_host: memcached-gcxt cache_port: "11211" cache_prefix: gcxt my.cnf: | [mysqld] log-bin = mysql-bin haha = hehe创建：
[root@kub-k8s-master prome]# kubectl apply -f configmap.yaml configmap/test-config4 created结果如下面data内容所示：
[root@kub-k8s-master prome]# kubectl get configmap test-config4 -o yaml apiVersion: v1 data: cache_host: memcached-gcxt cache_port: "11211" cache_prefix: gcxt my.cnf: | [mysqld] log-bin = mysql-bin haha = hehe kind: ConfigMap metadata: annotations: kubectl.kubernetes.io/last-applied-configuration: | {"apiVersion":"v1","data":{"cache_host":"memcached-gcxt","cache_port":"11211","cache_prefix":"gcxt","my.cnf":"[mysqld]\nlog-bin = mysql-bin\nhaha = hehe\n"},"kind":"ConfigMap","metadata":{"annotations":{},"name":"test-config4","namespace":"default"}} creationTimestamp: "2019-10-21T08:30:24Z" name: test-config4 namespace: default resourceVersion: "191270" selfLink: /api/v1/namespaces/default/configmaps/test-config4 uid: 2a8cd6e7-db2c-4781-b005-e0b76d26394b查看configmap的详细信息：
# kubectl describe configmap示例ConfigMap文件：
[root@kub-k8s-master prome]# vim config-map.yml --- apiVersion: v1 kind: ConfigMap metadata: name: config-map namespace: default data: special.how: very special.type: charm 创建 [root@kub-k8s-master prome]# kubectl apply -f config-map.yml configmap/config-map created2.1 通过环境变量使用
(1) 使用valueFrom、configMapKeyRef、name、key指定要用的key:
[root@kub-k8s-master prome]# vim testpod.yml --- apiVersion: v1 kind: Pod metadata: name: dapi-test-pod spec: containers: - name: test-container image: daocloud.io/library/nginx env: #专门在容器里面设置变量的关键字 - name: SPECIAL_LEVEL_KEY #这里的-name,是容器里设置的新变量的名字 valueFrom: configMapKeyRef: name: config-map #这里是来源于哪个configMap key: special.how #configMap里的key - name: SPECIAL_TYPE_KEY valueFrom: configMapKeyRef: name: config-map key: special.type restartPolicy: Never 创建pod [root@kub-k8s-master prome]# kubectl apply -f testpod.yml pod/dapi-test-pod created测试：
[root@kub-k8s-master prome]# kubectl exec -it dapi-test-pod /bin/bash root@dapi-test-pod:/# echo $SPECIAL_TYPE_KEY charm(2) 通过envFrom、configMapRef、name使得configmap中的所有key/value对儿 都自动变成环境变量：
[root@kub-k8s-master prome]# kubectl delete -f testpod.yml pod "dapi-test-pod" deleted [root@kub-k8s-master prome]# cp testpod.yml testpod.yml.bak [root@kub-k8s-master prome]# vim testpod.yml --- apiVersion: v1 kind: Pod metadata: name: dapi-test-pod spec: containers: - name: test-container image: daocloud.io/library/nginx envFrom: - configMapRef: name: config-map restartPolicy: Never这样容器里的变量名称直接使用configMap里的key名：
[root@kub-k8s-master prome]# kubectl apply -f testpod.yml pod/dapi-test-pod created. [root@kub-k8s-master prome]# kubectl exec -it dapi-test-pod /bin/bash root@dapi-test-pod:/# env HOSTNAME=dapi-test-pod NJS_VERSION=0.3.3 NGINX_VERSION=1.17.1 KUBERNETES_PORT_443_TCP_PROTO=tcp KUBERNETES_PORT_443_TCP_ADDR=10.96.0.1 PKG_RELEASE=1~stretch KUBERNETES_PORT=tcp://10.96.0.1:443 PWD=/ special.how=very HOME=/root KUBERNETES_SERVICE_PORT_HTTPS=443 KUBERNETES_PORT_443_TCP_PORT=443 KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443 TERM=xterm SHLVL=1 KUBERNETES_SERVICE_PORT=443 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin special.type=charm KUBERNETES_SERVICE_HOST=10.96.0.1 _=/usr/bin/env2.2 作为volume挂载使用
(1) 把1.4中test-config4所有key/value挂载进来：
[root@kub-k8s-master prome]# kubectl delete -f testpod.yml pod "dapi-test-pod" deleted [root@kub-k8s-master prome]# vim volupod.yml --- apiVersion: v1 kind: Pod metadata: name: nginx-configmap spec: containers: - name: nginx-configmap image: daocloud.io/library/nginx volumeMounts: - name: config-volume4 mountPath: "/tmp/config4" volumes: - name: config-volume4 configMap: name: test-config4 创建pod [root@kub-k8s-master prome]# kubectl apply -f volupod.yml pod/nginx-configmap created进入容器中/tmp/config4查看：
[root@kub-k8s-master prome]# kubectl exec -it nginx-configmap /bin/bash root@nginx-configmap:/# ls /tmp/config4/ cache_host cache_port cache_prefix my.cnf root@nginx-configmap:/# cat /tmp/config4/cache_host memcached-gcxt root@nginx-configmap:/#可以看到，在config4文件夹下以每一个key为文件名value为值创建了多个文件。
